APS D-Mod Co2 Magazine for Marui 17 18c, APS ACP601 & D-Mod Deluxe Airsoft GBB - AirsoftGoGo Keychain Included High Quality O-Ring for Co2 sealing is used Fully Compatitible with Aftermarket Airsoft Pistol using the similar system Patented design of the End Cap of better gastification of Co2